A needlestick injury can be a scraping or piercing wound typically caused by an accidental encounter with the sharp point of a needle. Needlestick injuries are an occupational hazard in the medical community because they can cause transmission of blood-borne diseases. Some of the more threatening of these diseases are the hepatitis B virus (HBV), the hepatitis C virus (HCV), and the Human Immunodeficiency Virus (HIV), the virus which causes AIDS.
Protocols exist for reporting needlestick injuries in medical environments but for a variety of reasons they are frequently ignored. As a result, a true accounting of these injuries is not available. Rather than delay ongoing medical procedures when experiencing a needlestick, healthcare workers often gamble with the odds of contracting a blood-borne disease and take no action. At least half of such events go unreported because injured healthcare workers downplay the risks, or fear stigmatization and professional consequences1. Indeed, in a survey of 255 responders to a questionnaire submitted via e-mail to all staff in a National Health Service trust, where results were compared to occupational health department (OHD) records, 135 (53%) completed the questionnaire and the results revealed that fifteen of 31 consultants (48%), 12/36 junior doctors (33%), 0/39 midwives (0%), and 8/30 theatre staff (27%) reported having had at least one intraoperative needlestick injury during the previous year. Ninety-three percent of consultants, 67% of junior doctors, and 13% of theatre staff had not complied with local protocols. The reasons given were stated to be the length of time it takes to do so (48%) and a perceived low infection risk of the patient (78%) suggesting that a maximum of 16% of intraoperative needlestick injuries were dealt with in accordance to local policy7.
Years ago, as authorities became aware of this tendency, new rules and guidelines were issued to reduce the incidence of such injuries, the majority of which were considered preventable. Still, worldwide needlestick injuries were estimated to have transmitted 16,000 HCV, 66,000 HBV, and 1,000 HIV infections in the year 2000 among healthcare workers, with attributions due to these injuries constituting approximately 39%, 37%, and 4.4% respectively2.
Many needlestick injuries are caused by accidental encounters with solid needle electrodes that are placed in patients' bodies for intraoperative monitoring purposes. These incidents generally occur in the operating room where the OR staff is at risk of such injuries when moving and positioning anesthetized patients before, after, and during their surgeries. Skin punctures from these solid needle electrodes are thought to account for less than half of these incidents, but that may be a gross underestimation because needlesticks from needle electrodes are known to be less effective in transferring disease than needles that are hollow—such as hypodermic needles and sharp percutaneous instruments—so brushing-off these injuries is far more common.
Anesthesia personnel are especially vulnerable since they often work on or around the head of a patient to do things such as adjust the airway, relocate a temperature sensor, or assist the surgeon by pulling on the patient's head to open the spaces between the vertebrae, all while the patient's head may be harboring more than a half-dozen subdermal needle electrodes placed at widely separated locations. Needle electrodes in patients' heads are often not visible due to their being covered by hair, making them ‘easy to miss’.
The accidental encounter generally occurs when an unsuspecting surgeon, anesthesiologist, surgeon's assistant (SA), nurse anesthetist (CRNA or RNSA), nurse (RN), or other staff member either brushes-against or applies force to reposition a patient and receives a skin-puncture from a subdermal needle electrode in the process. This kind of needlestick injury usually occurs when the electrode, due to this applied pressure, has its sharp end forced outward through the patient's skin and through the medical-grade adhesive tape that is normally used to cover the electrode and hold it in place. Naturally, all of the variety of adhesive tapes used in the OR are easily punctured and offer no protection in these circumstances.
Although needlestick injuries typically cause only minor bleeding and visible trauma, the risk of viral infection obviously exists. Not so obviously, a needlestick injury can put a patient at risk if the injured health professional carries a disease since the needle's tip reenters the patient's subdermal tissue, once the applied pressure is removed, and is dragged through more of the patient's tissue when it is withdrawn. In addition, when needle electrodes are removed from patients, they are sometimes mishandled and left on tables or the floor due to haste or forgetfulness and, instead of being put into sharps containers, nurses and rushed cleanup crews fail to recognize the discarded wires as having needles on their ends and they sometimes become stuck. When they are not recognized as needle electrodes and are thought to simply be wires that are to be discarded, the needle electrodes are sometimes placed in normal refuse containers where they pose a risk to unsuspecting garbage handlers. It should be understood that these needles remain hazardous well after their liquid contamination has dried. Although the infectiousness of both HIV and HCV decreases within a couple of hours, the infectiousness of HBV remains stable during desiccation and remains infectious for more than a week3.
After a needlestick injury, a protocol, with its specified procedures, should be followed to minimize the risk of infection. When the affected person follows protocol and reports the injury, it results in a loss of time for both the affected person and the facility in which the injury occurred. Taking care of each reported needlestick injury is estimated to cost institutions about $2,500 in the short term in the US4. Immediately following the injury, the affected area is supposed to be rinsed and washed thoroughly with soap and water without “milking-out” blood from the wound (per a recommendation of the CDC). Unless the potential source is known to be negative for HBV, HCV, and HIV, post-exposure prophylaxis (PEP) is supposed to be initiated, ideally within one hour of the injury6. Typically this is done in the emergency department or the occupational health office. Soon afterward, lab tests of the injured party are obtained for baseline studies for HIV and an acute hepatitis panel and, for immunized individuals, also for HB surface antibody; further, the status of the potential source of pathogens, unless already known, is similarly tested5. Follow-up of exposed individuals includes HIV testing by enzyme immunoassay to monitor for possible seroconversion for at least 6 months after exposure, and counseling1.
Despite these dangers, there is currently no readily available product that can significantly reduce or eliminate the risk of needlestick injury from needle electrodes. Securing needle electrodes to patients' bodies with a thick, foam tape is a procedure that is occasionally used to provide a small amount of protection since it increases the distance between the needle tip and the OR staff, presents a squeegee action to the needle as it passes through the tape, and, to some degree, distributes contact forces over a larger area. The lack of a truly effective product, however, is certainly the main reason that punctures from electrode needles are as common as they are in cases where intraoperative monitoring is employed. Indeed, three needlestick events occurred from inserted subdermal needle electrodes that were used during one intraoperatively monitored surgical procedure at one hospital in Cincinnati in early 2011, and the news of that situation spread rapidly throughout the Perioperative Surgery department.
To address the need for, and to provide the benefits of a system that could greatly reduce or even eliminate the risk of needle-electrode needlesticks among OR and other hospital staff, the present product was invented to provide puncture-resistant barriers wherever needlestick-susceptibility exists. The use of this product would greatly reduce the chances that the highly sharpened ends of needle electrodes would be able to threaten healthcare workers.
For protection from needle electrodes that are inserted into patients' heads and often not secured by lengths of tape, a first embodiment of the present invention was devised as an appliance in the form of a substantially thin and generally flexible puncture-resistant “hat” that can cover all regions of the head into which needle electrodes are typically inserted. This hat is lightly kept in-place preferably with embedded or attached elastic material.
For protection from needle electrodes that are inserted into generally hairless regions of patients' bodies, the present invention is a device which incorporates a puncture-resistant barrier, and a self-adhesive-material coating on at least a portion of its underside region for easy attachment to the patient and for securing the electrode lead(s). The self-adhesive material will generally be a medical-grade pressure-sensitive-adhesive which adheres with the application of light pressure. The device can be packaged the way EKG stick-on electrodes are supplied in quantities, nested together on a larger release-material-covered flexible sheet for easy peel-off at the time of use. In a similar fashion, it can be packaged in quantities, nested together in a linear array on a similar type of substrate (of width sufficient to cover, for example, the narrower dimension of the device, and of length sufficient to support any number of the devices) which can be rolled into a roll resembling a roll of tape, enabling the product to be sold in the form of a roll of multiple devices from which individual devices may be conveniently peeled, manually or automatically from a dispenser. In addition, intervening sections of both the flat-sheet and rolled substrates can be perforated so that individual devices may be easily separated from others on their common substrates by tearing the substrates at the perforations.
A third embodiment of the present invention reduces the danger of needlesticks by replacing the needle electrodes with an entirely new type of monitoring electrode that can be made with a hard-wired lead, similar to the hard-wired lead of a needle electrode, or it can be made with a connector “button” to which a snap-on electrode lead can be attached in much the same way that a snap-on electrode lead connects to a stick-on EEG electrode. Each configuration of this third embodiment requires sterilization and sterile packaging since they incorporate several relatively short, skin-piercing needles (resembling the group of needles on the insulation-piercing component in alligator clips of telephone-repairperson's handsets), or other skin-puncturing implements, that are part of a component that is attached to its adhesive-bearing underside surface. This component is either mounted flat against the undersurface or it is supported by a flexible conductive strap that can preferably be corrugated or folded-back-onto itself and implemented to prevent subtle movements of the pad from affecting the penetration-depth of the needles. (Skin-penetration makes the low-impedance body-contact that is so important in achieving the high degree of common-mode-signal-rejection that enables acquisition of microvolt-level biological signals in the presence of electrical interference.) Advantages of this third embodiment include (1) easier attachment to the patient, (2) a substantial reduction or elimination of needlestick-injury-risk associated with needle electrodes since detaching and discarding these models could be safely accomplished by attaching them to each other or attaching them to a discardable penetration-resistant film or sheet, supplied and packaged with them as safe disposal aids, and (3) for the snap-connected models, reduced cost of electrodes due to the reusability of the snap-on leads. This second advantage can be contrasted with the task of removing needle electrodes where their thin, sharp needles are held by their leads during removal after which they can (and too-frequently do) “fly-around” and puncture the skin of anyone nearby.
A fourth embodiment of the present invention is envisioned and would be like the third except that in place of physical skin-penetrating components it would use an electrically conductive chemical or chemical compound that penetrates the skin's dermal layer to achieve a higher degree of electrical conductivity than is possible with conventional stick-on EEG electrodes. Similarly, advantages of this embodiment would include (1) reduced cost of electrodes due to the reusability of the snap-on leads, (2) easier patient attachment, and (3) complete elimination of needlestick-injury-risk since no mechanical penetration of the patient's skin occurs with its use. This embodiment would require sterilization and sterile packaging.